For the IDF it was one of the bloodiest battles of the entire war with Hamas.

On July 19 and 20, only days after Israel began the ground offensive against Hamas, an Israeli armored personnel carrier, with nine soldiers inside from the Golani Brigade, crossed into the Hamas stronghold of Shejaia in Gaza City. It was an older APC, built in the 1970s, and was in dubious mechanical condition. The armor protecting the APC was several inches less thick than the newer models in the IDF.

That such an older, outdated and unprotected APC was sent into battle would become the subject of a bitter controversy within the IDF. These conditions set the seeds for a national tragedy that still haunts Israelis.

Sometime early Sunday morning, July 20, the APC stalled out in one of the Hamas neighborhood's densely packed streets. Two soldiers got out to see if they could fix it. But this was Hamas's backyard. Scores of terrorists were densely packed throughout the neighborhood, in apartment buildings, mosques, tunnels, underground passage ways and alleyways.

Then Hamas struck. Terrorists fired an anti-tank missile at the APC which penetrated the thin armor and apparently hit a stockpile of munitions inside. The APC exploded in a fiery blast.

Soldiers who witnessed the explosion were helpless. No one could have survived.

Still, even worse, an IDF drone showed that up to half a dozen Hamas terrorists had converged on the burning vehicle, which prevented an immediate effort to retrieve the APC along with the bodies of the soldiers inside. In addition, the prospect of another explosion inside the APC kept other soldiers from the Golani Brigade at bay.

The Times of Israel later provided an English summary of an exclusive report from the Israeli website Walla.com that reported details it had obtained from a classified IDF report of the incident It described what happened next, "At that point, the Golani Brigade's command, assessing that the soldiers in the APC had been killed, ordered other soldiers in the field to converge on the APC and evacuate body parts from within the vehicle. However, the soldiers were wary of nearing the APC, as they feared weaponry inside could set off a secondary explosion at any moment. The soldiers also reported hearing shouting in Arabic in the vicinity of the APC, according to Walla.

"Golani Command decided to summon IDF combat engineers to erect a dirt barrier around the APC and seclude it from the surrounding area.

"The subsequent IDF investigation concluded that Hamas gunmen had already reached the vehicle and taken parts of Shaul's body by this time.

Hamas later released an ID photo of Shaul, along with his army ID number."

The IDF retrieved the APC, but it made a grim discovery in identifying the remains of the soldiers who perished inside the vehicle. The IDF could only find the remains of six soldiers, whereas it knew seven had been inside when the vehicle exploded.

Shortly thereafter, Hamas made a startling announcement on that Sunday evening, The terrorist groups claimed it had kidnapped the seventh soldier, St.-Sgt. Oron Shaul. The military wing of Hamas broadcast a statement that "Israeli soldier Shaul Oron is in the hands of the Kassam Brigades."

To prove its claim, Hamas released photos of Oron's ID and other items he carried on him.

To further bolster its claim, Hamas hacked into Oron's Facebook page and posted claims in Arabic, Hebrew and English that it had him. Hamas taunted the Israeli public with cruel and sadistic propaganda on the hacked Facebook page.

On Monday, July 22, as international news reports carried Hamas's claim of capture of Oron, the IDF really had no idea what happened to the soldier.

The only statement made by the IDF at that point was that Oron was missing in action. Even two days later, the IDF still did not know if he had been kidnapped by Hamas or was dead.

Kidnapping an Israeli soldier is one of the highest priorities for Hamas, since Israel has proven willing to trade large numbers of imprisoned terrorists to get back just one soldier, as happened in the case of Gilad Schalit. The news of Hamas's alleged kidnapping triggered wild celebrations in Gaza.

The IDF and Israeli intelligence agencies initiated a massive manhunt for Oron, to no avail. "We simply did not know whether he was alive or not," an Israeli military official told me, "or whether Hamas had killed him or whether Hamas had simply kidnapped his body. But we had immediately set up a dragnet around the entire area to encircle the terrorists and prevent them from leaving the general area. We knew we did not have much time."

The dragnet proved porous, as Hamas terrorists had many ways of escaping, especially through the network of tunnels they had built. But in hacking Oron's Facebook page, Hamas may have inadvertently given away the location of the terrorists who had him or his body. That's because whenever a Facebook account is accessed, Facebook's servers automatically keep a record of the Internet Protocol address where the account was accessed. IP addresses can provide a location of the IP address where the Facebook account was hacked.

In addition, there was a remote possibility that Oron had been carrying his cellphone, although Israeli soldiers are not supposed to take their cellphones into battle. But if he had done so, then it was theoretically possible that Hamas had hacked into the mobile Facebook application on his phone.

If the Israelis could obtain the Facebook server data as soon as possible, they might have had a chance to find the whereabouts of the terrorists who took Oron.

Israel made an urgent appeal to the FBI for help in trying to determine the remote source or information that would be stored on Facebook servers indicating the location where Oron's page had been hacked into. Upon receiving the request from Israel in Washington on July 21, the FBI immediately issued a preservation letter to Facebook ordering them to preserve all data saved on their server pertaining to the Oron's account.

At 4:25 p.m. on July 21, the FBI contacted a United States Attorney's Office in a nearby district to initiate the legal process to get a court order to serve Facebook for server information on the account belonging to the soldier.

"Due to HAMAS status as a Designated Terrorist Organization (DTO), there is a great effort to locate those who kidnapped and/or killed ORON," read an FBI email to the U.S. Attorney's Office. "HAMAS is already using the kidnapping as propaganda, which is material support to a DTO."

In the email, the FBI noted there was unusual activity on Oron's Facebook account after his kidnapping and said it needed more information from Facebook that it could only obtain with a court order to be able to fully determine what "HAMAS was doing with Oron's Facebook account and possibly his phone."

Was the U.S. Attorney's Office in a position, the FBI wanted to know, to immediately obtain a court order for the FBI to deliver to Facebook? Shortly thereafter, the U.S. Attorney's Office thought it was near ready to be able to immediately obtain a court order. But before it could obtain such an order, it needed specific information on Oron's Facebook account that it could present to the judge.

At the same time, back in Israel, the reports of the possible kidnapping of began to dominate Israeli news as the Israeli public became more anxious by the hour. The IDF meanwhile would not confirm that he had been kidnapped or that he was dead or alive, only that he was missing in action.

To be sure, the IDF was using all other available intelligence means — technical and human — to try to determine the fate of its missing soldier.

The attempt to secure information via the soldier's Facebook account was just one of the multiple efforts being made by the IDF but deemed a "worthy shot" by a senior Israeli military official. So as these other efforts were under way, time was ticking away on the Israeli request to the FBI to get vital Facebook server information on the Hamas terrorists who had either kidnapped Oron or seized his remains.

The more time elapsed, the less the odds of finding the soldier.

But the next day, July 22, the U.S. Attorney's Office received a startling response from the FBI: "Thank You for your effort, input and assistance. I regret to inform you we have been denied approval to move forward with legal process. We were told by our management we need a MLAT [Mutual Legal Assistance Treaty] in order to continue to assist our partner with the request in question." Those words put an immediate halt to the Israeli request.

An MLAT is a standardized legal agreement between the United States and other countries that spells out the legal and diplomatic protocols in processing requests for legal information pertaining to court cases in either the United States or in another country.

MLATs go through various bureaucratic channels, usually take weeks to process and would generally be used for non-pressing legal matters in which the United States or another country was carrying out a legal process such as a prosecution involving a citizen of another country.

Prosecutors familiar with their use say that an MLAT would definitely not be used in an urgent life-or-death intelligence or counter-terrorist incident, especially with a close ally such as Israel. "In a pressing court matter, there is no way the USG would invoke an MLAT with a close ally," said a veteran prosecutor who has worked on international counter-terrorism cases.

Law enforcement officials knowledgeable about this incident say both prosecutors and the FBI were shocked at the turn of events. "This sudden reversal was devastating," said one law enforcement official who was intimately familiar with this incident. "For those working this case, they felt this decision was tantamount to a death sentence. Nothing less."

And thus, the FBI was never able to supply Israel with any information on Oron's Facebook account that might have led to the location of the soldier or his remains that had been seized by Hamas.

It's also clear that there was no guarantee that this information, once obtained, would have located the terrorists or Oron. Three days later, on July 25, after an exhaustive forensic investigation, the IDF concluded that Oron Shaul was dead. "Today, July 25, 2014, at 14:40, a special committee lead by the chief rabbi of the IDF, announced the death of the IDF infantry soldier, Staff-Sergeant Oron Shaul, who was killed in battle in Gaza on July 20, 2014," the army's statement said.

To this day the soldier's body, as well as that of another soldier who died in battle, Lt. Hadar Goldin, remain in the hands of Hamas. Recent reports indicate Hamas is interested in negotiating a swap for Palestinian prisoners held by Israel and that Israel has appointed an IDF officer to head up these negotiations.

Lingering questions remain from this episode. Senior law enforcement officials, on condition of anonymity, have told me that the withdrawal of authority to the FBI to retrieve the Facebook records for Israel came from the attorney general's office.

But why would Eric Holder's office reverse such a request, especially since it was so urgent and came from such a close ally? And if it was not the attorney-general's office who reversed the request, and then who did? It could only have come from someone very senior in the US government.

This article was based on interviews with U.S. law enforcement officials, and Israeli military officials and a review of official documents.

Originally from the Jerusalem Post.

Steven Emerson is executive director of The Investigative Project on Terrorism. He was a correspondent for CNN and a senior editor at U.S. News and World Report. Read more reports from Steve Emerson — Click Here Now.